Reproduction processes are known wherein positive-working photopolymerizable elements and negative-working photosensitive elements are exposed imagewise (e.g., through a phototool) to form non-tacky and tacky image areas. For example, positive-working photopolymerizable elements are described in Chu and Cohen U.S. Pat. No. 3,649,268, and negative-working photosensitive elements are described in Cohen and Fan U.S. Pat. Nos. 4,174,216 and 4,191,572. The image is developed by toning with a suitable toner that selectively adheres to the tacky image areas. Excess toner, which may be present, is then removed from the non-tacky areas. The resulting image is a proof of the original, or can be used in a transfer process to place the image on another surface. Multilayer proofs, such as surprint proofs, can be made by repeating the process steps with different phototools and colored toners.
In view of the increasing importance of proof-making in the printing industry, improved toners and applicators for applying these toners are desired. Some improvements in toners are described in U.S. Pat. No. 3,620,726 to Chu and Manger, which discloses pigmented cellulose acetate toner particles; U.S. Pat. No. 3,909,282 to Gray, which discloses mixtures of those toners with silica particles; U.S. Pat. Nos. 4,330,613 and 4,397,941 to Fickes, which disclose pigmented cellulose acetate toners surface coated with an antistatic agent and a slip agent; and U.S. Pat. Nos. 4,565,773 and 4,546,072 to Matrick, which disclose toners similar to those of Fickes, but employing polydimethyl siloxanes and polymeric quarternary compounds as the antistatic agent.
Application of any of the above described toners, as well as other prior art toners, to tacky image areas of photosensitive elements may present a problem in that it is difficult to completely remove the toner from the non-tacky areas of the elements. After cleanup, some undesirable stain is usually present in the non-tacky areas. The term "background color" as used herein refers to the color present in the non-tacky background areas of an exposed and toned positive-working or negative-working photosensitive element prior to any step being taken to remove toner excess therefrom. Background color is the sum of two components: "stain", which is the color not removed from the background color areas by exhaustive wiping of the areas; and "clean-up", which is the color that may be removed from the background color areas by wiping, air impingement, or the like.
It is known to add silicone oil to the above described toners to improve their stain characteristics. However, the addition of silicone oil does not readily reduce the stain of pearlescent pigments to the industry accepted level of approximately 0.5 or less. Thus, there is a need for improved pearlescent toners.